Welcome to the world of children's vision!

Archive for August, 2012

Visual memory and visualization

Visual Spatial Memory: the ability to recall the spatial location of an object or stimuli. The ability to be able to recall, identify, or reproduce a design or dominant feature of an object. Visual memory is important throughout school.

Example: Being able to picture a lost object; seeing a printed word and developing a mental picture to the corresponding object.

Activity: Memory Card Games

Visual Sequential Memory: Ability to view and then recall a sequence of numbers, letters or objects in the order they were originally presented.

Visualization is the ability to remember (mentally) a picture or object seen and mentally manipulate the image in different ways. We can then form a mental image that is used in the present or in the future. This ability is essential in spelling, oral math and to be able to recall scenes, events, instructions.

The child must first consider the first form. Then he must find which of the four forms which, once assembled with the first, will be a perfect square.

Visual Speed & Span of Perception: The rate and amount at which information is being handled in visual processing. For example, the ability to rapidly compare visual configurations and identify two figures that have similar or identical or to identify some particular detail that is buried in distracting material. It is also the process of selectively concentrating on one aspect of the environment while ignoring other things.

Example: quickly and efficiently copying an assignment off the chalkboard with only a few glances vs. needing to glance at the chalkboard after every one to two words or bits of information is copied.

Automaticity

Once all of these skills are developed, it is important for them to become automatic so they take up less brain power to use. In order to have efficient visual information processing skills, you have to learn the skills well to the point where they become easy.

Automaticity is the key in efficient learning.

Learning to read and write is a human’s most difficult task in his whole life. Reading and writing are very complex tasks that require many visual perceptual, auditive and tactile abilities.

The optometrist specialized in vision training must assess all visual and perceptual abilities. This is why assessment of these skills takes more time.

Vision therapy

Vision therapy is a series of motor, visual and perceptual activities designed to enhance those skills. Because these skills are learned between 0 and 6 years old, they can be learned again or trained to obtain a maximum of efficacy.

Two clinical studies

In 2010, Dhingra and coworkers have analyzed the relationship between different perceptions (visual, auditory, kinesthetic and tactile) and academic performance of a number of children.

They used parts of standardized tests that specifically measured the adequacy of these perceptions (including McCarthy Scales of Children’s Abilities and WISC III-R).

First, performance in reading and spelling were significantly associated (students who are good readers are also good in spelling), and these two academic areas were closely linked to the three perceptual aspects mentioned above. On the other hand, mathematics achievement was linked only to the auditory and visual perception. Thus, the results indicate, among other things, that visual and auditory perceptions play a crucial role in learning.

Another study, by Goldstand in 2005, was designed to compare visual and perceptual skills between children with or without moderate school problems in reading and examine the impact of visual deficits among them.

The authors compared the results of seventy-one seventh-grade students, where 46 had no problems reading and 25 had moderate problems in reading. They used scores from visual screening tests of visual perception, tested visual-motor integration, and school performance. In addition, they have subsequently compared academic performance and processing of visual information between children who were successful or not in the visual tests.

Visual deficits were found in 68% of participants, and in more boys than girls. Readers with reading problems had significantly poor overall school performance and lower scores in the vision screening tests than the good readers. Participants who successfully completed the vision screening had significantly better results in visual perception than those who failed.

Visual and perceptual functions distinguish well between children with and without mild learning difficulties. The high incidence of visual problems in children who do not always succeed in school tells us that it is important to assess the visual and perceptual deficits in schoolchildren with difficulties in academic performance.

Conclusion

We discussed the principal perceptual skills a child must master in order to better process visual information both at school and elsewhere. Vision and perception affect all aspects of children’s lives. In a sense, the visual perception is the process of visual thinking more than the eye itself.

Directionality

Directionality incorporates up, down, ahead, behind, and any combination thereof into the equation. It also means projecting these directions including left and right out into space. Again, a person must understand these concepts as they relate to themselves before they can apply them to other things.

Directionality is very important in decoding letters.

If a child does not have this concept properly integrated, earning to read can be very confusing. For example, the letters “b,” “d,” “p,” and “q,” all look like the same symbol if he or she does not have any concept of orientation.

FACT: Research has shown that children who still have reversal problems after age 8 will likely have problems developing good reading skills.

These skills, however, can be trained or learnt by vision training.

An important function that bridges laterality and directionality is our eyes.

Efficient eye movement skills are essential in developing good directionality skills. If your eyes cannot move across a page smoothly and accurately, this could mean that you are at risk for reversals and coding problems, because how we scan a letter is important when coding it to the brain.

There are two different directionalities:

– Graphical directionality: depending on whether the child is right or left handed, letters or shapes are not intrinsically formed in the same direction (from right to left or left to right). But, writing in English requires a graphical movement from left to right (even for left-handed children). Relationship with reversals of letters and/or numbers.

– Spatial directionality: the projection outside the organism in space and/or on paper. The child must match his outside relations of space with the inside relations of his body. The observation of relationships between objects in space.

Bilateral Integration and body awareness

Bilateral integration is another visual-spatial skill that is important. This is the ability to effectively use both sides of the body separately (like typing) and/or simultaneously (like riding a bicycle).

Bilateral integration is another visual spatial skill that is important. This is the ability to effectively use both sides of the body separately (like typing) and/or simultaneously (like riding a bicycle).

This skill cannot be developed fully unless laterality is learned well, too. If you do not have the concept of the difference between both sides of your body, it is very difficult to learn how to coordinate them.

Body schema or body awareness concerns the integrated knowledge of all parts of the body as reference points in space (relationship with gross motor, general coordination, sports, etc.), since the body acts as a point of reference in space when we move. This is the set of process which detects the position of body parts in space.

Visual Analysis Skills

Visual analysis, or visual discrimination, is used to identify, sort, organize, store and recall visually presented information. It is the ability to take in visual information, remember it and apply it later.

Children with poor visual analysis skills often have trouble learning the A, B, C’s and recognizing words or simple forms even when presented repeatedly; for example, they may correctly read the word “house” in one sentence and incorrectly read “horse” two lines later. These kids tend to mistake words with similar endings or beginnings, generalize when grouping objects. They also have a hard time understanding size and magnitude, (a cup of water in a tall glass and a cup of water in a shallow bowl are not seen as equal amounts).

Signs & Symptoms of Visual-Analysis Dysfunction

Trouble learning the alphabet

Trouble recognizing words

Mistakes words with similar beginnings

Overgeneralizes – confuses minor likenesses and differences

Does not recognize the same word if repeated again on a page

Trouble with remembering and writing letters and numbers

Distractible

Short attention span

Problems concentrating

Traces or touches figures

Difficulty with understanding instructions

Hyper or hypo active

Subskills of Visual Analysis

Figure Ground: An ability to attend to or search for a specific form or feature while simultaneously ignoring irrelevant information. Example: looking for a specific piece of information when reading or searching for a specific tool in a toolbox full of tools.

Activity: Where is Waldo? – Hidden Pictures

Visual Form Recognition/Form constancy

The ability to discriminate differences in forms or shapes. This includes differences of size, shape, color and orientation. Form constancy is the recognition that visual information in a form is consistent in spite of the object, size in the back of the eye, or location.

Example: DOG = dog = Dog

Visual discrimination is thus the ability to observe subtle similarities or differences among shapes or symbols. It is related to visual attention.

Form perception is the ability to recognize basic shapes that will constitute letters and/or numbers. Many children have difficulties to see and copy shapes on paper.

Visual Closure: The ability to recognize clues presented visually that allow him or her to determine the appearance of the final product without all the details being present.

Example: Being able to complete a word when only part of the word is seen; recognizing what will appear in a picture before it is completed.

In this activity, the child must recognize which of the examples in the bottom represents the figure on top.

Before a child id really ready to learn at school, there are a lot of prerequisites that he or she must control from 0 to 6 years old. Gross motor activitiesinvolve the whole body (as in walking, running, jumping, throwing, swimming, etc..) They require intervention and coordination of large muscle groups. To do this, the child must overcome gravity. Non-locomotor movements involve changes in position or posture without moving in space (eg, throwing, catching, rotating, bending, straightening, pushing, pulling, stretching, etc.). Locomotor movements involve moving the entire body in space (eg walking, running, jumping, crawling, rolling, bicycling, swimming, skiing, etc.). Stable position or maintenance of posture for some time, requires monitoring of muscular effort (eg maintain a sitting position, stand on one foot or two, etc.).

Development of fine motor skills in children is a way to access the autonomy necessary to intensify sensory exploration and interaction with people and the physical environment, which stimulates all other areas of development. The development of fine motor coordination refers to the movements of the hand and arm required to reach, grasp, release or manipulate objects. Control of fine motor skills usually involves the stability and strength of the neck, trunk and arms, as well as the coordination of the hand and eyes, the perception of touch, good visuospatial perception, the ability to coordinate motor movements, body awareness in space and coordination between the two sides of the body. Mastering fine motor skills allows children to manipulate toys with small parts, dress and undress independently and use scissors and, most of all, instruments for writing.

The relationship between fast, smooth and efficient eye movements and reading performance is obvious. Vision is often considered an exclusively sensory act. In fact, normal vision does require precise eye movements. When we learn to read, in particular, we must be able to develop and implement small rapid eye movement, or perfectly adapted saccades, so that our eyes can move from one word to the next word and one line to the other.

Visual skills refer to how the eyes function together as in focusing when reading or with any other task in near vision, how the eyes are aligned at what they look, etc.

Visual perceptual processing, or visual information processing, is a set of skills we use to gather visual information from the environment and integrate them with our other senses. The ultimate purpose of visual perception is to derive understanding and meaning from what we are experiencing. This process allows the development of schemes to derive meaning from what we see.

Visual perceptual processing is very important, but especially so when learning. Without visual perceptual processing, you would not be able to accurately learn to read, give or get directions, copy from the board or from a book, visualize objects or past experiences, remember things visually, have good eye-and coordination, integrate visual information with our other senses to do things like ride a bike, play ball, or hear a sound and be able to visually recognize where it is coming from (like an ambulance), just to name a few.

Visual perceptual processing can be broken into three components – visual spatial skills, visual analysis skills and visual integration skills. Just like anything else that is broken into components, these skills work together or build upon each other to help you function in you visual environment.

Visual Spatial Skills

These are the skills we use to understand directional concepts to organize our visual space. This is how we visually project our body coordinates out into the world.

For example: when you say, “It is over to the left,” the “to the left” has no meaning unless it has a point of reference. So actually, you are really saying to the left of where YOU are. If you don’t know where your body is, it is hard to know where things are in relation to you.

Visual spatial skills require observing an object, then accurately reporting its relationship in space relative to your own self.

Signs & Symptoms of Visual-Spatial Dysfunction

Lack of coordination and balance (clumsy)

Difficulty learning left and right

Reverses letters or numbers when writing or copying

Difficulty with activities involving rhythm

Not good at sports

Does not cross the midline when doing tasks (switches objects from hand to hand)

Does not use nondominant hand for support when writing or copying

Rotates body when writing or copying (again to not cross the midline)

Laterality

Laterality is an internal self awareness of two body sides and knowing they are different. It requires good balance, vestibular function and an awareness of a body midline (an invisible line that divides your body in half).

FACT: During a study at the Southern California College of Optometry, 73.8% of children already determined to have a learning disability failed tests used to assess laterality and directionality.

Some behaviors observed in kids that have not developed laterality are the following:

Nondominant hand not used for support

Switches hands so they do not cross the midline of their body with them

Motor overflow

Rotates body (again so as not to cross over the midline)

These tendencies happen in all young kids, but if confusion with laterality occurs after 8 years old, it can potentially cause problems.

Laterality (on self) is the precursor of directionality (orientation in space).

A person must understand laterality on their person before it can be applied in space. This means if you do not know the two sides of your body (left and right), how can you know what to call the two sides of the room? We always learn how to judge where things are by first learning how to relate it to ourselves.

When you start applying left and right concepts to your external visual space, you are beginning to learn directionality.

VISION AND LEARNING OR READING PROBLEMS

Vision is our most important sensory modality: 80% of what we learn is achieved through our visual system. However, we easily underestimate this important information system (the visual system).

In many instances, children who manifest visual problems or whose visual abilities are not well integrated will have difficulties to perform properly in school.

Unfortunately, many still believe that a child who has “good vision” (a visual acuity of 20/20 or 100% at far) should be performing well in school and that learning or reading difficulties are then not related to their vision…

To really understand what we, optometrists specialized in visual training, mean by the word “vision”, we will discuss once again, briefly, the three prinicpal components of vision:

THE OPTICAL COMPONENT

This component determines if the child can see clearly at far: he may be nearsighted (myopia), farsighted (hyperopia) or have astigmatism. But “seeing clear” is not the whole aspect of vision. By experience, we know that 95% of children who have learning or reading disabilities can see clearly at far. Near vision is thus more important than far vision and has to be assessed.

Amongst the problems we find in this component are: child reads or writes very close, vision can be blurred in books, child cannot sustain proper concentration or attention, he does not understand easily what he reads. Reading glasses (for the brain) can help children decode or perform better and sustain focus longer while reading.

THE FUNCTIONAL COMPONENT

Another aspect of vision is how the eyes function together. Here, we must assess how well the focusing mechanism of the eyes can perform, how the eyes are aligned (visual-motor coordination), and if eye tracking (eye movements) is easy, smooth, precise. Needless to say that adequate eye movements are essential to good reading! Unfortunately, this functional component is not always tested in a conventional eye examination.

Amongst the problems we find here are: the child cannot focus on what he reads or writes more than a few minutes (homework takes forever), the child tires easily when reading because of the muscular effort required, and eye movements are jerky, imprecise and head movements are most often used (instead of eyes).

Children with learning disabilities often have trouble following an object with their eyes and move their eyes from one place to another. Instead of precise movements, their eyes show jerking movements with lots of delays. This visual problem causes activities such as playing ball, make a straight line or read a line of text become very difficult.

(Jean Ayres, Sensory Integration and the child)

THE PERCEPTUAL COMPONENT

The perceptual abilities of the child are the refinement and the end-product of all visual abilities: perceptual-motor abilities are related more directly to the ability to decode visual information.

Amongst the perceptual problems we can find are: form perception is weak, eye-hand coordination is difficult, visual and/or auditive memory is low, fine motor control of the hand is inefficient.

All these visual and perceptual abilities are of great importance: they help make the child succeed in school. We must remember that for children, the most difficult task in life is to learn to read and write. A complete visual-perceptual examination is thus required to be able to analyse how the child performs visually and perceptually.

WHAT CAN BE DONE ABOUT IT?

This is the next evident question. As we said, sometimes reading glasses are required to help the child cope with the visual stress of reading and writing.

But most of the time vision training will also be needed. Vision training consists of a programmed series of activities to enhance visual and perceptual abilities. Visual training thus consists of gross motor activities, fine motor activities, visual motor activities and perceptual activities.

SYMPTOMS CHECKLIST

Here is a list of different symptoms whose parents are constantly sharing with us in a consultation. I distinguished visual symptoms from symptoms related to reading and writing.

Visual symptoms:

Headaches

Blurred vision

Double vision

Eyes get tired easily

Reads quite or very close

Writes very close to paper

Turns head when reading/writing

Bad posture while reading or writing

Closes or blocks one eye while reading

Eyes are often red, itchy, burning

Eyes blink a lot

Rubs eyes often

Eyes blink very often

Complains about his (her) eyes often

Symptoms related to learning/reading/writing

Loses his (her) place when reading

Must read a few times to understand

Does not understand easily what is read

Follows text with a finger

Mixes up letters or numbers

Follows text with head

Reverses letters or numbers

Must read aloud to understand reading

Reads very slowly

Lack of concentration, attention

Takes lot of time to do homework

Daydreams a lot

Other behavioral symptoms

Is quite hyperactive

Is rather clumsy, trips over things often

Is always dropping things

Problems regarding gross motor skills

Problems regarding fine motor skills

VISUAL-MOTOR-PERCEPTUAL EXAMINATION

The visual-perceptual tests for children who manifest learning/reading problems will generally be done in two separate visits at our clinic:

First, a general visual examination will be done to analyze following factors: